Recently, a non-contact IC tag has been utilized to perform the personal certification, and article managements have been conducted to manage articles such as goods, storage articles and loadings by attaching a non-contact IC tag to articles such as goods, storage articles or loadings for management. For example, the article management has been conducted by attaching an IC tag which has recorded information such as production condition, stock state, cost information and usage condition to the articles and optionally further confirming the recorded information by an interrogator or the like.
An electronic circuit incorporated in the non-contact IC tag or the like comprises a circuit line which forms a coil antenna and a terminal portion composed of a plane flat surface which connects an IC chip and a jumper line. The flat surface of the terminal portion is generally a larger area than that of the circuit line to improve the connection reliability in view of the position movement of the connection to the IC chip and the jumper line, when the plane flat surface of the terminal portion is connected to the IC chip and the jumper line.
However, if there is a large difference between the line width of the connected circuit line and the size of the plane flat surface of the terminal portion (for example, see Patent reference 1), there is a case that the circuit line breaks because the stress concentration is caused at a position near the junction where the terminal portion is connected to the circuit line, when the electronic circuit is folded.
For example, as indicated in FIG. 2, if the circuit line 1 and the terminal portion 3 are connected at the junction 5, the outline of the side edge of the terminal portion 3 is a straight line, and the angle θ between the side edge of the terminal portion 3 and the circuit line 1 is large, there is a case that the circuit line is folded and the circuit line breaks because the stress concentration is caused at a position near the junction 5 where the terminal portion is connected to the circuit line when the electronic circuit is folded along the short side direction of the circuit line 1.
If the circuit line of the electronic circuit is broken, the function of the IC tag is lost, and the management can not be performed by confirming the recorded information.    Patent reference 1; JP2004-227273 A1